The goal of this project is to continue to generate monoclonal anti-idiotypic antibodies to study the heterogeneity of anti-native DNA antibodies in patients with systemic lupus erythematosus. We hope to identify both public and private idiotypes on anti-native DNA antibodies shared among unrelated patients with SLE. We will determine whether idiotypes are stably expressed throughout the course of a patient's illness, whether they correlate with antigenic specificity or tissue injury, whether idiotype positive B and T lymphocytes can be identified, and whether patients develop anti-idiotypic antibodies or anti-idiotypic T lymphocytes. In addition, serum and cells from family members and from normals will be assayed for expression of these idiotypes. These studies should provide insight into the immunogenetics and pathogenesis of SLE and may increase our understanding of autoantibody production.